Search Results (213)

In this work, we optimized three key factors for rotational molding composites: the recycled polyethylene (rPE) content, the pigment (Cp) content, and the process parameter-peak internal air temperature (PIAT). We studied the influence of rPE, Cp, and PIAT on various composite properties. These included mechanical properties (e.g., elastic modulus E), impact strength (MFEsp), surface characteristics (wettability measured by contact angle θ and IR spectroscopy), thermal stability (by DTA–TG analysis), environmental stress cracking resistance (ESCR in hours), and the amplitude of the third harmonic β of the ultrasonic back-wall signal. The IR spectroscopy and contact angle results indicate that adding rPE and pigment slightly increases the composite’s surface hydrophilicity. The results show that PIAT strongly influences all the characteristics of the composites studied. Depending on its percentage, the introduction of rPE can either improve or worsen these composite properties. A correlation was found between β, ESCR, MFEsp, and E, demonstrating that β can serve as a quantitative indicator of internal stress (IS) in rotomolded parts. The recommended optimal composition is rPE 30%, Cp 0.5%, and PIAT 195 °C. Under these conditions, the composite exhibits minimal internal stress and optimal performance, which in turn extends the service life of rotomolded products. Four nomograms were developed: rPE = f(MFEsp, Cp, PIAT) and rPE = f(β, Cp, PIAT), which make it possible to quickly determine MFEsp and β of a product based on the actual PIAT, taking into account rPE and pigment content in the composite (they also allow selecting the rPE and pigment content in the composition depending on the required MFEsp). Full article

This study aimed to systematically characterize the pyrolysis characteristics and combustibility of six typical tree species across different altitude gradients in southwestern Yunnan, providing references for fuel management and selection of potential fire-resistant species in this region. Thermogravimetric analysis (heating rate: 20 °C·min⁻¹, air atmosphere) was employed to obtain TG-DTG curves of bark, branches, and leaves. The Coats–Redfern integral method was applied to calculate kinetic parameters, and principal component analysis was conducted for comprehensive combustibility evaluation. The results demonstrated the following: (1) The pyrolysis process of all species underwent the following four distinct stages: moisture evaporation, holocellulose decomposition, lignin decomposition, and ash formation. Among these, holo-cellulose decomposition constituted the primary mass loss stage. Significant differences in pyrolysis characteristics were observed among different plant parts, with leaves and bark exhibiting lower initial pyrolysis temperatures; (2) The activation energy ranged from 56.05 to 86.41 kJ·mol⁻¹ across different components, with branches requiring the highest energy for pyrolysis; (3) Principal component analysis based on multiple indicators yielded the following comprehensive combustibility ranking: Pinus yunnanensis > Betula alnoides > Lithocarpus henryi > Quercus acutissima > Cunninghamia lanceolata > Myrica rubra; and (4) The combustibility assessment results integrating multiple variables (total mass loss rate, stage-specific mass loss, activation energy, and ash content) showed significant differences from the analysis based solely on activation energy, verifying the necessity of a multi-dimensional comprehensive evaluation. Full article

Polyvinyl chloride (PVC), owing to its excellent electrical properties and low cost, is widely applied in the inner insulation and outer sheath of cables. To achieve early fault warning based on characteristic gases, this study integrates experimental testing with molecular simulations to systematically reveal the decomposition and gas generation characteristics of different PVC layers under electrical and thermal stresses. The results indicate that inner-layer PVC under electrical stress predominantly generates small-molecule olefins and halogenated hydrocarbons, while outer-layer PVC during thermal decomposition mainly produces hydrogen chloride, alkanes, and fragments of plasticizers. The surrounding atmosphere significantly regulates the gas generation pathways: air promotes the formation of CO₂ and H₂O, whereas electrical discharges accelerate the release of unsaturated hydrocarbons such as acetylene. By employing TG-FTIR, ReaxFF molecular dynamics, and DFT spectral calculations, a normalized infrared spectral library covering typical products was established and combined with the non-negative least squares method to realize quantitative deconvolution of mixed gases. Ultimately, a diagnostic system was constructed based on the concentration ratios of characteristic gases, which can effectively distinguish the failure modes of inner and outer PVC layers as well as different stress types. This provides a feasible approach for early detection of cable faults and supports intelligent maintenance strategies. Full article

Rice cultivation accounts for roughly 10% of worldwide anthropogenic greenhouse gas emissions, making it a significant source of methane (CH₄) Despite modest observational constraints, estimates of worldwide CH₄ emissions from rice agriculture range from 18–115 Tg CH₄ yr⁻¹. CH₄ is a potent greenhouse gas, and its oxidation produces tropospheric ozone (O₃), which is harmful to public health and crop production when combined with nitrogen oxides (NOx) and sunlight. Elevated O₃ levels reduce air quality, crop productivity, and human respiratory health. This study presents an AI-driven framework that combines ensemble learning, hyperparameter optimisation (HPs), and SHAP-based explainability to enhance CH₄ emission predictions from rice paddies in India, Bangladesh, and Vietnam. The model consists of two stages: (1) a classification stage to distinguish between zero and non-zero CH₄ emissions, and (2) a regression stage to estimate emission magnitudes for non-zero situations. The framework also incorporates O₃ and asthma incidence data to assess the downstream impacts of CH₄-driven ozone formation on air quality and health outcomes. Understanding the factors that drive optimal model performance and the relative importance of features affecting model outputs is still an ongoing field of research. To address these issues, we present an integrated approach that utilises recent improvements in model optimisation and employs SHapley Additive ExPlanations (SHAP) to find the most relevant variables affecting methane (CH₄) emission forecasts. In addition, we developed a web-based artificial intelligence platform to help policymakers and stakeholders with climate strategy and sustainable agriculture by visualising methane fluxes from 2018 to 2020, ensuring practical applicability. Our findings show that ensemble learning considerably improves the accuracy of CH₄ emission prediction, minimises uncertainty, and shows the wider benefits of methane reduction for climate stability, air quality, and public health. Full article

A new construction of a custom-made, low-cost, electronic-nose-applying eight-TGS-type gas sensors manufactured by Figaro Inc. was assembled. The gas sensors were used to collect response signals caused by changes in gas composition from clean air to the studied odor, to which the sensors were exposed. In addition, modulation of sensor heater temperature was implemented in order to register complementary information useful for differentiation between the studied odor categories. An automatic mechanism was to open the gas sensor chamber, allowing sensors exposure to the studied gas and cleaning of sensors in the condition of a closed chamber. Sensor cleaning was conducted by forcing a clean air current through the application of a pneumatic pump. Three-dimensional printing was used to manufacture the sensor chamber. The Raspberry PI microcomputer was used for control of the measurement procedure and data collection. The operation of the device could be controlled by a web-based interface from a connected laptop or smartphone. The device was applied to the monitoring of the development of spoilage of soft fruits like strawberries and raspberries. Periodic measurements were performed in an automatic manner. A dedicated system of separation of the measured sample from the gas sensor array, preventing heat flow, was designed. Technical challenges encountered during the measurement are presented. Full article

Background/Objectives: The anatomical complexity of the auricular region poses a unique challenge for contact interventional radiotherapy (IRT, modern brachytherapy), especially in maintaining close conformity between the applicator and skin surface. Air gaps can arise due to the irregular shape of the ear, potentially compromising dose coverage. This study evaluates the dosimetric impact of air gaps in HDR IRT for non-melanoma skin cancer (NMSC) of the ear. Methods: Ten patients treated with contact IRT using alginate as supporting material were retrospectively analyzed. Treatment plans were recalculated using both the TG-43 and the TG-186 formalism. CTV coverage and organ-at-risk dose parameters were evaluated within the two formalisms. Results: CTV coverage was comparable between algorithms (mean V95% 96.2% vs. 94.4%, V100% 89.6% vs. 86.7%, and V150% 2.6% vs. 2.5% for TG-43 vs. TG-186; p > 0.05), while the ipsilateral eye D2cc decreased from 4.0% (TG-43) to 3.2% (TG-186). In silico simulations showed that increasing air gaps reduced skin dose progressively (up to ~15% at 5 mm), whereas alginate thickness produced only a mild dose increase (<5%) across the tested range. Overall, small air pockets (<1 mm) did not substantially alter global dosimetric metrics, although local underdosage may occur at gap locations. Conclusions: This study underscores the importance of accounting for material heterogeneities and geometric uncertainties in anatomically complex regions through advanced dose calculation algorithms. Full article

In this study, we evaluate a phosphorus-based fire retardant (HR Prof) on Norway spruce using Simultaneous Thermal Analysis (STA: TG/DTG/DSC), Gas Chromatography–Mass Spectrometry (GC–MS), and bench-scale mass-loss measurements. Relative to the untreated reference, HR Prof re-routes decomposition toward earlier dehydration and transient char, simplifies the evolved gas mixture in the 150–250 °C range, and reduces burning intensity during 600 s of radiant exposure. Across 150/200/250 °C, identified components fell from 20/24/51 (reference) to 5/9/9 (HR Prof); no phosphorus-containing volatiles were detected in this window. Mass-loss tests showed a lower average burning rate (0.107 vs. 0.156%·s⁻¹) and a smaller cumulative loss at 600 s (64.2 ± 9.5% vs. 93.7 ± 2.1%; one-way ANOVA, p < 0.05 for percentage loss). STA was conducted in air; the transient char formed at an intermediate temperature is oxidized near ~600 °C, explaining the low final residue despite earlier charring. A count-based Poisson model corroborated the significant reduction in volatile component richness for HR Prof (p < 0.001). The cross-method correspondences—earlier condensed-phase dehydration/char → leaner volatile pool → lower and flatter burning-rate profiles—support a condensed-phase-dominated protection mechanism within the conditions studied. Full article

Livestock and poultry manure emits substantial amounts of ammonia and non-CO₂ greenhouse gases of nitrous oxide and methane, contributing simultaneously to climate forcing and air quality degradation. However, few studies have provided an integrated quantification of ammonia, nitrous oxide and methane emissions across multiple species and provinces in China. This study established a coupled provincial inventory for 2013–2023 and applied the Logarithmic Mean Divisia Index (LMDI) to identify socioeconomic drivers. Results show that NH₃ emissions declined slightly from ~4.1 Tg in 2013 to 3.95 Tg in 2023 (−3.7%), while N₂O increased from 2.1 to 2.3 Tg (+9.5%) and CH₄ rose from 3.1 to 4.2 Tg (+35%). Consequently, the aggregated global warming potential increased by ~24% (from ~1100 to ~1370 Tg CO₂-eq). Hogs were identified as the dominant contributor across gases. High-emission provinces contributed disproportionately, whereas metropolitan and western provinces reported marginal levels. LMDI decomposition revealed that affluence and technological intensification were the main drivers of growth, partially offset by production efficiency and labor decline. This study provides one of the first integrated multi-gas, multi-species, and region-specific assessments of livestock manure emissions in China, offering insights into targeted mitigation strategies that simultaneously support carbon neutrality and air quality improvement. Full article

Anthropogenic methane (CH₄) emissions lead to global warming and air pollution. China has recently crafted a bottom-up approach to regulate its anthropogenic CH₄ emissions; however, emissions during and after the COVID-19 lockdown have not been fully investigated using this updated method. In this study, we calculate provincial-level anthropogenic CH₄ emissions in 2022 using this official bottom-up approach, explore feasible mitigation pathways, estimate reduction potentials, evaluate the economic cost of abatement, and assess the social benefits of reductions. The results show that China’s total anthropogenic CH₄ emissions in 2022 were estimated to be 52.6 (49.8–55.6) Tg, approximately 47.6%, 39.5%, and 12.9% of which were from agricultural activities, energy utilization, and waste management, respectively; forest burning contributed 0.35 Gg. Using currently available approaches, China’s total yearly anthropogenic CH₄ emissions can be reduced by around 33%, with an average reduction cost of USD 130.9 million per Tg of CH₄. The social cost of CH₄ was estimated to be USD 231.8 per metric ton, indicating that the negative impact of annual anthropogenic CH₄ emissions was equal to 0.07% of China’s GDP. Despite the consistency between top-down inversions and our bottom-up inventory, we argue that the official guideline may underestimate China’s soil CH₄ emissions due to changes in soil substrate availability, relative humidity, and the active layer of methanogens from global warming. Methods to improve current estimation accuracy are discussed. Owing to the slow international diffusion rate of methane-targeted abatement technologies, China needs to develop relevant technologies with independent intellectual property rights. Full article

The substitution of hazardous, environmentally persistent solvents (NMP and DMAc) with more sustainable alternatives (ETAc and GBL) in fabricating flat sheet polyactic acid (PLA) membranes via nonsolvent-induced phase separation for air filtration applications was the focus of this study. The polymer-solvent affinity was first evaluated using Hansen solubility parameters, confirming suitable Relative Energy Difference (RED) values (<1) for all solvent candidates. Dope solutions prepared with biodegradable solvents demonstrated higher viscosity compared to those prepared with environmentally persistent solvents. These biodegradable solvent systems also exhibited slower precipitation rates during membrane formation. This resulted in spongelike cross-sectional morphologies, contrasting with the combined fingerlike and spongelike structures observed in membranes fabricated with environmentally persistent NMP and DMAc. Thermal analysis revealed that membranes fabricated with biodegradable solvents exhibited superior thermal stability with higher glass transition temperatures (Tg = 54.39–55.34 °C) compared to those made with environmentally persistent solvents (Tg = 49.97–50.71 °C). Membranes fabricated with ethyl acetate (ETAc) showed the highest hydrophobicity (contact angle = 115.1 ± 9°), airflow rate (12.7 ± 0.28 LPM at 0.4 bar) and maintained filtration efficiency at values greater than 95% for 0.3 μm aerosols. Full article

In recent years, membrane separation technology has undergone continuous advancements. Microfiltration (MF) membranes, as an important type, are usually prepared by electrospinning—a simple and efficient method. This study reports the development of crosslinked polyvinyl alcohol/polyethylene glycol (cPVA/PEG) nanofiber membranes through a combination of electrospinning and chemical crosslinking, investigating the effects of different crosslinking concentrations on the membrane morphology, surface wettability, and tensile properties. Comprehensive characterization was carried out by using scanning electron microscopy (SEM), a Fourier-transform infrared spectrometer (FTIR), an X-ray diffractometer (XRD), a thermogravimetric (TG) analyzer, differential scanning calorimetry (DSC), a contact angle tester, a universal testing machine, etc. The results showed that at the crosslinking concentration of 15%, the cPVA/PEG fiber membrane achieved a breaking stress of 29.07 ± 2.60 MPa, a breaking strain of 77.60 ± 6.02%, and a porosity exceeding 43%. SEM, FTIR, XRD, TG, and DSC analyses collectively confirmed the occurrence of chemical crosslinking within the membrane structure. The cPVA/PEG-15 membrane exhibited no observable shrinkage or curling upon water contact, combined with excellent hydrophilicity and lipophilicity in the air. These properties indicate that the membrane can serve as a novel functional membrane substrate (e.g., as hydrophilic separation layers) and is expected to play an important role in fields such as seawater desalination and wastewater treatment, demonstrating significant application potential. Full article

Chronic rhinosinusitis (CRS) is characterized by sinonasal inflammation, mucus overproduction, and edematous mucosal tissue. This inflammatory condition is characterized by mucosal thickening, nasal obstruction, facial pain or pressure, hyposmia, and nasal discharge. The aim of this research was to clarify a potential role for the receptor for advanced glycation end-products (RAGE) in mouse nasoantral epithelium in perpetuating pro-inflammatory cytokine elaboration similarly expressed by CRS patients. Specifically, wild-type (WT) mice and transgenic (TG) mice overexpressing RAGE in sinonasal epithelium (RAGE TG mice) were maintained in room air or subjected to secondhand smoke exposure using a nose-only delivery system (Scireq Scientific, Montreal, QC, Canada) for five days per week over a 30-day period. Histological analysis was performed using staining for RAGE. Tissue lysates were analyzed for pro-inflammatory cytokines. We observed increased RAGE expression in sinus tissue following SHS exposure and in sinuses from RAGE TG mice in the absence of SHS. We also discovered elevated T helper (Th)1 products (TNF-α, IL-1β, IFN-γ) and Th2/Th17 (IL-5, IL-13, IL-17A) cytokine abundance in SHS-exposed WT and SHS-exposed RTG tissues compared to room air controls. These findings highlight the pivotal role of RAGE signaling in the exacerbation of inflammatory processes, particularly in the context of chronic inflammation induced by smoke exposure. The study expands our understanding of the RAGE signaling axis as a key contributor to the progression of smoke-related lung and sinonasal pathologies. Targeting RAGE-mediated pathways could represent a novel therapeutic strategy to mitigate the progression of chronic sinusitis associated with smoke exposure. Full article

Our previous study examined the stratosphere-troposphere exchange (STE) of air mass and ozone using ERA5 and MERRA2 reanalysis data and observations for 2007–2010. Their analysis applied a lower stratosphere mass budget approach, with the 380 K isentropic surface serving as the upper boundary of the lowermost stratosphere. This study employs a dynamic isentropic surface fitted to the tropical tropopause, providing an update to the results using the static 380 K boundary. Additionally, we improve the numerical scheme for deriving the mass of the lowermost stratosphere. Under this new framework, the air mass upward flux at the isentropic surface in the tropics increases from 19.3 × 10⁹, 19.3 × 10⁹, and 22.0 × 10⁹ kg s⁻¹ in our previous study to 21.9 × 10⁹, 20.9 × 10⁹, and 26.3 × 10⁹ kg s⁻¹ in the present study for ERA5, MERRA2, and observations, respectively. The global ozone fluxes across the fitted isentrope become −347.6, −362.5 and −368.4 Tg yr⁻¹ as compared to −345.7, −359.5 and −335.6 Tg yr⁻¹ at the 380 K level from our previous study for ERA5, MERRA2 and observations, respectively. The corresponding extratropical ozone fluxes are −539.3, −541.3 and −565.5 Tg yr⁻¹ versus previous estimates of −538.1, −542.5 and −527.8 Tg yr⁻¹. The increased role of tropical cirrus clouds near the tropopause is also highlighted under the updated framework in observations. The contribution of cloud heating to tropical air mass flux increases from 2.0% in our previous study to 8.2% in the present analysis, while for ozone, the corresponding contribution increases from 1.8% to 8.1%. We further show that the improved estimate of the change rate of mass in the lowermost stratosphere has an impact on seasonal ozone STE results from chemistry climate models presented in another of our previous studies. These findings provide new insights into the processes governing stratosphere-troposphere exchange. Full article

Detection of soil pollution by petroleum products is necessary to remedy threats to economic and human health. Pollution by hydraulic oil often occurs through leaks from forestry machinery such as harvesters. Electronic noses equipped with gas sensor arrays are promising tools for applications of pollution detection and monitoring. A self-made, low-cost electronic nose was used for differentiation between clean and polluted samples, with two types of oils and three levels of pollution severity. An electronic nose uses the TGS series of gas sensors, manufactured by Figaro Inc. Sensor responses to changes in environmental conditions from clean air to measured odor, as well as responses to changes in sensor operation temperature, were used for analysis. Statistically significant response results allowed for the detection of pollution by biodegradable oil, while standard mineral oil was difficult to detect. It was demonstrated that the TGS 2602 gas sensor is most suitable for the studied application. LDA analysis demonstrated multidimensional data patterns allowing differentiation between sample categories and pollution severity levels. Full article

College student military training is an organized, high-intensity, short-term militarized activity in China; this study aims to explore the differences in thermal perception between different intensities of military training. Questionnaires and microclimate measurements were conducted during summer military training in cold regions, including the Protective and Rescue Training and Assessment (PRTA), Formation Training (FT), the Shooting and Tactical Training and Assessment (STTA), the Route March (RM), and Dagger Practice (DP). The results indicated that (1) there was no significant correlation between the intensity of the activity and votes on thermal perception. The strongest thermal sensations, the lowest comfort, and the lowest thermal acceptability were experienced during FT, with a lower activity intensity. (2) Air temperature (T_a), globe temperature (T_g), relative humidity (RH), mean radiant temperature (T_mrt), and solar radiation (G) had significant effects on the TSV. (3) FT involved the lowest neutral temperatures (NUTCI/NPET), while DP and RM training had the highest NUTCI and NPET values, respectively. The neutral temperature range during military training was narrower compared to that in other aerobic activities. This study reveals, for the first time, the non-traditional correlation between military training intensity and thermal perception, confirming the specificity of thermal sensations in mandatory training and providing a theoretical basis for optimizing military training arrangements and developing thermal protection strategies. Full article